Hybrid prosthesis and delivery system

ABSTRACT

A hybrid endoprosthetic device comprises a stented tubular part and a branched tubular body connected such that a main lumen of the stented tubular part communicates with a main lumen of the branched tubular body. The branched tubular body has multiple branch lumens for connection with natural vessels of the vasculature, and includes at least one branch lumen for access to facilitate delivery and implantation of the hybrid endoprosthetic device by an endovascular step in a hybrid surgical procedure. The hybrid endoprosthetic device is configured to replace a part of the aorta and common iliac artery. A delivery system for use with the device is also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage filing under section 371 ofInternational Application No. PCT/GB2017/052602, filed on Sep. 6, 2017,and published in English on Mar. 15, 2018 as WO 2018/046917, and claimspriority to Great Britain Patent Application No. 1615219.1 filed on Sep.7, 2016, the entire disclosures of each of the prior applications arehereby incorporated by reference herein

TECHNICAL FIELD

This disclosure relates to surgical procedures and provides a prostheticdevice for use as a hybrid endograft in a patient requiring surgery,particularly an intervention to treat a vascular pathology.

BACKGROUND OF THE INVENTION

Parts of the vascular system may develop degenerative defects over time,and one such defect is an aneurysm. An aneurysm is an abnormal bulge inthe wall of a blood vessel leading to a localised weakening of the bloodvessel wall with an increased potential for leakage, rupture andinternal bleeding. The aneurysm may cause significant dilation of thenatural lumen of the blood vessel compromising natural blood flow. Thepresent disclosure relates to an endograft suitable for insertion intothe aneurysm sac in the defective blood vessel to restore the vessellumen dimensions to those of the natural blood vessel before theaneurysm developed and thereby occlude the aneurysm sac. The discloseddevice is suitable for endoluminal treatment of an abdominal aorticaneurysm (AAA) or Thoracoabdominal aortic aneurysms (TAA).

Aortic aneurysms are discussed in the reference Crawford E S, Crawford JL, Safi H J, et al: Thoracoabdominal aortic aneurysms: Preoperative andintraoperative factors determining immediate and long-term results ofoperations in 605 patients. J Vasc Surg 3:389-404, 1986. Crawford andcolleagues, recognised a correlation between aneurysm extent andclinical outcome, and proposed a classification which defines aneurysmsas extent types I, II, III, and IV. Type I aneurysms involve all or mostof the descending thoracic aorta and the upper abdominal aorta. Type IIaneurysms involve all or most of the descending thoracic aorta and allor most of the abdominal aorta. Type III aneurysms involve the lowerportion of the descending thoracic aorta and most of the abdominalaorta. Type IV aneurysms involve all or most of the abdominal aorta,including the visceral segment. Types II and III are most difficult torepair because they involve the thoracic and abdominal segments of theaorta. Conventional methods for treatment of weakened portions of thevasculature include surgical replacement of the affected portion of theaorta, or a more conservative, minimally invasive endovascular repair.

In surgical intervention, the affected part of the blood vessel can beexcised and replaced with a prosthetic graft. This invasive approach isnormally performed under general anaesthesia with cardiopulmonaryby-pass, so that the patient's abdomen or thorax can be opened and theprosthesis sutured in place of the aneurysmal vessel. Consequently, themethod requires the time of a skilled surgeon and prolonged recoveryperiods for the patient in hospital. Prosthetic grafts normally used forsuch replacement are typically made from polyester fabric, which may bewoven or knitted, and may be sealed with a sealant, for example gelatineor collagen.

More recently endovascular repair techniques have been developed inwhich an endovascular device is introduced using a catheter. Whencorrectly placed in the defective natural vessel so as to bridgenon-aneurysmic parts of the vessel, a stent of the endovascular deviceis expanded and the catheter removed. Since the catheter can beintroduced via an artery, such as the femoral artery, the techniquerequires only minimally invasive procedures and consequently the patientshould be able to recover more quickly. The procedure was firstdescribed by Parodi (Annals of Vascular Surgery vol 5, pages 491-499,1991 and U.S. Pat. No. 5,578,072), and the technique is rapidlyreplacing conventional surgery as the preferred method of treating AAAand TAA.

The endovascular repair techniques use endoprosthetic devices which areplaced within the patient using bespoke delivery systems designed todeliver the endoprosthetic device in a compact “packaged” form forintraluminal delivery, and including removable restraining means,allowing the endoprosthetic device to be delivered, positioned, andfinally selectively deployed. When the endoprosthetic device isdeployed, the delivery system is removed, allowing the surgicalprocedure to be completed.

Hybrid procedures combine a conventional or modified surgical procedurewith an endovascular intervention procedure and are feasible in selectedhigh surgical risk patients. For example use of hybrid proceduresprovides an alternative to open repair in high risk surgical patientswith complex aortic pathology.

A vascular endoprosthesis apt to exclude an aneurysmal portion of theaorta is disclosed in U.S. Pat. No. 8,740,971 B2 the content of which isincorporated herein by reference.

Whereas there is a continuing need to improve surgical procedures andendoprosthetic devices suitable for addressing patient needs,endoprosthetic devices and methods disclosed herein offer the ability tocreate an iliac anastomosis with reduced risk of detrimental tensionwhilst having sufficient scope for manoeuvre during the procedure.Additionally, the endoprosthetic devices and methods disclosed hereinpermit blood flow sooner than before, with the ability to expel air froman endoprosthetic device by displacement through an open ended branchlumen of the endoprosthetic device by means of blood flow into theendoprosthetic device.

SUMMARY OF THE INVENTION

Using the hybrid endoprosthetic devices disclosed herein in a knownprocedure or in a procedure modified as disclosed herein permits rapidperfusion of visceral arteries by retrograde blood flow wherebysubsequent steps required to complete a procedure can be conductedthereafter at an acceptable pace with a foreseeable reduction in risk ofischemia or related problems normally associated with the knownprocedures. Therefore, the usual time pressure to complete the procedureis somewhat lessened. Significantly, the procedures described in thisdisclosure are designed to be carried out whilst the patient's heartremains beating, i.e. the patient is not supported on a “heart-lung”machine and so the procedure is classed as an “off-pump” procedure whichoffers numerous advantages.

The term “visceral arteries” is generally understood to encompass theceliac artery (celiac trunk), superior mesenteric artery (SMA), and therenal arteries. Connection of these arteries to an endoprosthetic deviceis provided for in the following disclosure using newly conceiveddevices and modifications thereof to be more particularly describedherein. In particular concerns about blood losses by leakage through thedelivery system are mitigated by a modification to the delivery systemfor the endoprosthetic device disclosed herein.

Broadly this disclosure relates to an endoprosthetic device that servesas a substitute for a deteriorated or injured part of a natural vessel,particularly the aorta-iliac region of the vasculature, and has lateralbranches for connection with visceral vessels. According to aspects tobe more particularly described hereinbelow, a device enabling earlyperfusion in a procedure is disclosed, and a modified delivery systemfor such a device, including a modification for improved sealingenabling reduced blood leakage during withdrawal of the delivery systemis disclosed.

In the present disclosure a hybrid endoprosthetic device comprises astented tubular part and a branched tubular body connected such that amain lumen of the stented tubular part communicates with a main lumen ofthe branched tubular body. Multiple branch lumens are available on thebranched tubular body for connection with natural vessels or for thepurpose of providing access for a surgical implement for manipulatingthe device, inserting a tool or ancillary device or for enabling asurgical step. The endoprosthetic device disclosed herein is suitablefor use as a thoracoabdominal hybrid device. Such a device would becontemplated for relining a diseased or deformed aorta to restore asubstantially normal lumen space, and also provide a substitute for thedescending aorta below the diaphragm. The hybrid endoprosthetic deviceis configured to communicate with dependent natural vessels by provisionof numerous branch lumens in an anticipated number sufficient to be ableto attach a corresponding natural vessel and communicate when attachedto the natural vessel with the natural lumen to allow flow of fluidtherethrough. Additionally, one or more of the branch lumens can beselectively used as an access branch to facilitate delivery andimplantation of the endoprosthetic device and optionally carry out stepsin the surgical procedure. At least a significant part of the aorta andcommon iliac may be treated and partially replaced by the endoprostheticdevice disclosed herein. The branched tubular body of the hybridendoprosthetic device disclosed herein may be bifurcated to providedevice limbs for respectively connecting with the iliac arteries.

The stented tubular part may be made from a fabric sleeve attached to astent element. A physiologically inert or benign material such as apolyester may be used.

Suitable ring stents and stent elements are disclosed in GB 2 491 477 Bthe content of which is incorporated herein by reference.

The one or more stents may be formed from multiple windings of a shapememory material, such as Nitinol or a resilient polymer.

The ring stents may include one or more stents which have a saddleshape.

The stent element may comprise at least one circular ring stent and morethan one stent which forms a saddle shape when attached within thefabric sleeve.

In other embodiments, other forms of stent can be used instead of or incombination with the aforesaid ring stents. Spiral, Z- or zig-zag, andtubular mesh types and combinations of any of these types with orwithout ring stents may also be suitable.

In an embodiment using ring stents having a saddle shape, these may bearranged in a series within the fabric sleeve along the longitudinalaxis of the stented tubular part, so that peaks and valleys of one ringstent are aligned with corresponding peaks and valleys of other ringstents in the series of ring stents.

The stented tubular part may be provided with hooks for retention of thestented tubular part in a selected position when deployed in a lumen ofa natural vessel. Suitable hooks are disclosed in U.S. Pat. No.9,398,964 the content of which is incorporated herein by reference.

The stented tubular part may be provided with radiopaque markers toimprove in vivo visualisation and to facilitate precise positioning ofthat part of the device. Suitable markers are disclosed in EP 1 736 116B1 the content of which is incorporated herein by reference. Theradiopaque markers may be made from a biocompatible heavy metal such asgold, platinum or tantalum, or tungsten for example, or a radiopaqueceramic contrast agent for example a ceramic bead based upon zirconia.

A collar to aid anastomosis to a natural vessel may be fixed around thehybrid endoprosthetic device at a portion thereof where the stentedtubular part and branched tubular body are connected.

The branched tubular body may be connected to the stented tubular partby sewing, for example by means of a sewable collar having a flangedportion. The sewable collar is suitable for facilitating anastomosis toa natural vessel into which the endoprosthetic device penetrates suchthat a main lumen of the stented tubular part communicates with a mainlumen of the branched tubular body to provide for blood flow through thenatural vessel and the endoprosthetic device.

The branched tubular body may be made from a woven fabric.

When the “endo” part i.e. the stented tubular part is to be insertedinto the lumen of a natural vessel such as the aorta, an incision in theaortic wall is made to provide an opening into which the stented tubularpart can be inserted. After insertion and deployment of the stentedtubular part into the natural vessel (aorta) blood flow is enabledthrough the lumen of the stented tubular part and into theendoprosthetic device. When blood is flowing through the hybridendoprosthetic device the surgeon can transect the main trunk of thediseased aorta and perform an anastomosis to the collar.

The orientation of the endoprosthetic device in relation to a supinepatient, where for reference purposes, the patient's head is assumed as“up” and the patient's feet are assumed as “down”, is such that afavoured embodiment of the hybrid endoprosthetic device is presenteduniquely as an inverted “Y” wherein the stented tubular part is directedupwardly into the thoracic aorta through a puncture below the diaphragm,and the branched tubular body is downwardly directed and presents abifurcated part for connection with the iliac arteries.

The stented tubular part may be provided with a series of radiopaquemarkers along its length to enhance visualisation through an imageguided delivery procedure to facilitate positioning thereof prior todeployment of the stented tubular part.

In an embodiment of a procedure for treating a patient affected by adefective natural vessel having an abnormally dilated section, aninitial surgical intervention is required to prepare the patient forreceiving an endoprosthetic device. The initial surgical interventionmay comprise a step of making an incision in the side wall of thedefective natural vessel at the abnormal defective section to provide anopening and preparing a purse string suture surrounding that opening.The purse string suture permits the natural vessel to be subsequentlyclosed around an inserted part of an endoprosthetic device to allow flowcommunication between the natural vessel and the endoprosthetic device.The natural vessel may be the thoracic aorta.

In an embodiment of a procedure for treating a patient with theendoprosthetic device, an open ended branch of the branched tubular bodyconfigured for attachment to a first patient iliac artery is attached toa side of the first patient iliac artery so that the attached branch isin flow communication therewith. A clamp is applied to the attachedbranch of the branched tubular body to temporarily close it. A secondopen ended branch of the branched tubular body configured for attachmentto a second patient iliac artery remains open in an initial stage of thesurgical procedure. In a subsequent stage air can be vented from thedevice via the second open ended branch by permitting blood flow andthereafter clamping the second open-ended branch until it is time tofinally connect it to the second patient iliac branch.

In an embodiment of a procedure for treating a patient with theendoprosthetic device, the stented tubular part of the endoprostheticdevice is inserted through the side wall incision prepared with a pursestring sutured part of the defective natural vessel. This may beassisted by transit over an inserted guide wire or cathetersubstantially as used in the established Seldinger wire technique andvariations thereof. Once inserted the stented tubular part of theendoprosthetic device may be deployed in an unaffected part of thenatural vessel beyond the purse string suture. In such an embodiment theopen lumen of the deployed stented tubular part of the endoprostheticdevice can be perfused through the aorta, whilst any entrapped air isdisplaceable through the second open ended branch of the branchedtubular body. Simultaneously, by retrograde blood flow, all visceralarteries are continuously perfused.

In an embodiment of a procedure for treating a patient with theendoprosthetic device, the visceral arteries are connectable in turnwith corresponding branch lumens of the branched tubular body.Throughout the time that all of these arteries are being connected,retrograde perfusion continues through the iliac connection to thebranched tubular body of the endoprosthetic device. Therefore, the riskof ischemia is remarkably diminished in comparison with prior techniquesand becomes negligible to virtually nil in all foreseeable cases.

Final distal anastomosis is accomplished at a section of theaortic/iliac arteries which is not defective (not aneurysmic). The finalstages may comprise distal end-to-end anastomosis of size-adjustedbranches of the branched tubular body with the natural vessels by anestablished inlay technique. Lumbar arteries to be treated, are ligatedor re-inserted into the endoprosthetic device. The treatment andre-insertion of the lumbar arteries can be facilitated by use of an openbranch of the branched tubular body which serves as an access branch.

After complete attachment of the endoprosthetic device the surgicalprocedure can be completed by resection of the diseased or defectivetissue constituting the aneurysm.

In all embodiments the delivery system for the endoprosthetic device maycomprise an elongate “delivery” shaft, (or a functional equivalent suchas a catheter or wire) upon which the endoprosthetic device is borne anddeliverable. The delivery shaft may be inserted in a branch lumen of theendoprosthetic device, which may be a dedicated access branch on thebranched tubular body of the endoprosthetic device by means of whichmanipulation of the device and the movement of the delivery shaft isachievable. Where a lumen guide wire is used, the elongate “delivery”shaft may be a catheter, or in the alternative the elongate “delivery”shaft is adapted to receive the guide wire through wire guidespositioned on the surface of the elongate “delivery” shaft at least nearthe distal tip.

The elongate shaft may be malleable to enable a user to form a curvaturetherein to facilitate delivery if required to better suit a patient'sanatomy.

The stented tubular part is delivered in a compact configuration topermit entry into a lumen and passage through the vasculature to a siterequiring treatment to “normalise” the lumen of a diseased part, and thestented tubular part is subsequently deployed by expansion to permit thestented tubular part to perform its function within a lumen.

In embodiments, the delivery system comprises a retractable sheath forcompactly restraining the stented tubular part to be introduced to thenatural vessel during the endovascular part of the surgical procedure.

The retractable sheath may be made from a physiologically benign lowfriction or slip polymeric material such as polytetrafluoroethylene(PTFE). The retractable sheath may alternatively be formed frompolyethyleneterephthalate (PET). The selected material should be onewhich is biocompatible and may be readily passed through natural vesselsor artificial lumens without sticking. The retractable sheath may besurface treated, for example to impart or enhance hydrophilic propertiesby applying a hydrophilic coating.

Suitable polymeric flexible materials for the retractable sheath may beselected from thermoplastic polymers, elastomers, and copolymers such asnylon, polyurethane, polyethylene (PE), polytetrafluoroethylene (PTFE),expanded polytetrafluoroethylene (ePTFE), fluorinated ethylenepropylene, polyether block amides (PEBA), polyimide, polyether etherketone, and polybutylene terephthalate.

The retractable sheath may be of a multi-layered construction offlexible, polymeric materials, such as multi-layered extrusions,optionally reinforced as by use of braided layered assemblies or laminarstructures incorporating bonding layers and reinforcements, orintermittent extruded composite extrusions and assemblies of variabledurometer characteristics.

In embodiments the delivery system comprises a hub having a throughboreadmitting an elongate delivery shaft and capable of receiving a partlength of the wall of a branch of the branched tubular body, inparticular cases, said branch being an access branch dedicated to thepurpose of the operation of the delivery system for controlling thepositioning and deployment of the endoprosthetic device.

The sheath may be designed to split (tear) in a predictable andcontrollable manner under application of appropriately applied force.Such force can be applied using a slitting tool which may beincorporated in the delivery system. By application of such force, thesheath may tear along its length and separate to release the stentedtubular part.

In embodiments the splittable sheath is retractable against a hubcomprising a splitter mechanism to facilitate removal of the retractedsheath from the stented tubular part after deployment within the naturalvessel beyond the purse string suture.

In embodiments the splitter mechanism may comprise one or more passive(static) slitter elements disposed to present slitter blade edges in theproximal-distal axial direction of the delivery shaft whereby the sheathbecomes split by retraction against these slitter blade edges of thepassive slitter elements.

The splitter mechanism may separate the splittable sheath in one or moreplaces, forming at least one longitudinal slit such that the sheath isremovable one piece, or optionally in more than one piece, for examplesplit longitudinally into halves.

The slitter elements may be made of a plastics material such as apolyamide, for example a nylon.

In embodiments of the splitter mechanism, a hub housing encompasses achamber which has internal side wall surfaces in which chamber there isa throughbore for passage of an elongate delivery shaft.

The delivery shaft may be of a malleable material so that a user mayshape the shaft, for example form a curvature in the shaft, prior tointroduction to a patient.

In embodiments the hub housing comprises separable parts which can befastened together about the delivery shaft and any tubular body, such asa branch lumen, that the delivery shaft has been introduced to. The hubhousing separable parts may be hinged along a common edge and havefastener parts at an opposite edge. The fasteners may have snap fittingparts. A separate release clip may be applied to releasably hold the hubhousing parts closed.

In alternative embodiments the hub does not comprise slitter elementsattached to the hub and in these embodiments the splittable sheath isdesigned to be peeled or pulled apart by incorporating tear lines,perforations, pre-cut parts, or introducing sutures which facilitateseparation in a controlled manner.

An option for such an embodiment lacking hub mounted slitter elements,is to provide a fine pull strand that is retrievable, passes within thesplittable sheath and is attached at the distal end of the splittablesheath, for example by a suture, the pull strand returning over thesplittable sheath to the proximal end, and which is thin enough to splitthe splittable sheath as it is withdrawn over the splittable sheath. Auser pulling upon the pull strand externally from the proximal end ofthe pull strand lifts the distal end of the pull strand and causes thepull strand to begin splitting the splittable sheath. Continued externalpull upon the pull strand by a user splits the splittable sheath fromdistal to proximal end. The proximal end of the splittable sheath may beattached to a pull wire or pull strap for retrieval of the split sheath.

The delivery system including the delivery shaft may be carefullywithdrawn after the stented tubular part is deployed within the naturalvessel beyond the purse string suture.

During the withdrawal process for removing the delivery system, there isa potential risk that blood loss may be increased due to leakage aroundthe elongate shaft past the delivery system via the dedicated accessbranch on the branched tubular body.

In order to address this potential risk, any embodiment of a deliverysystem for an endoprosthetic device as disclosed herein may use anelongate delivery shaft modified by presence of a stopper member that isslidable axially along the length of the elongate delivery shaft andconfigured to fit into the hub. In operational practice duringwithdrawal of the elongate delivery shaft, the stopper member would bestatic and captive within a part of the delivery system to perform itsstopper or sealing function, but the elongate delivery shaft would befreely movable relative to the stopper member. The stopper member isconfigured and sized to form a close fit within a branch lumen, forexample part of a dedicated access branch of the branched tubular bodyof the endoprosthetic device borne upon the delivery shaft andcontacting a part of the delivery system to form in combinationtherewith a fluid barrier, thereby to inhibit fluid flow by-passing thedelivery shaft length to leak beyond the delivery system.

The stopper member may be a moulded part having a curved, for examplepart-spherical or cylindrical surface for providing a valve surface toseat within a part of the delivery system, and compress a part of abranch lumen therebetween to provide a complete seal.

The stopper member may have a compressible resilient outer surface toensure close contact to perform its sealing function with the part ofthe branch lumen against a side wall of the hub throughbore. Theresilient outer surfaced stopper member may be slightly oversize withrespect to the width dimension of the hub throughbore to further improvesealing functionality.

The outer surface of the stopper member may comprise a siliconepolymeric material.

The stopper member has a throughbore which may be lined with a materialpromoting slip over the delivery shaft so that sliding of the shaftrelative to the stopper member is facilitated. Such materials include,PTFE and silicone-based materials such as Slick Sil® Liquid SiliconeRubber from Surface Solutions Group LLC.

In this embodiment the contacted part of the delivery system, thecontacting part of the dedicated access branch of the branched tubularbody, and the stopper member cooperate together to form a fluid(haemostatic) seal within the dedicated access branch during withdrawalof the delivery system. By this modification, the delivery shaft may beremoved and the risk of by-pass leakage around the delivery shaft isreduced.

The contacted part of the delivery system may be upon the internal wallsof the splitter chamber within the splitter mechanism, which walls mayat least in part define the throughbore of the hub.

Whenever the delivery shaft is withdrawn sufficiently within thededicated access branch, i.e. the tip of the delivery shaft is retractedtowards the hub, that part of the dedicated access branch through whichthe tip of delivery shaft has been already withdrawn can be clampedshut. After clamping the dedicated access branch, the delivery shaft andall other parts of the delivery system can be completely removed. Finalde-airing of the endoprosthetic device is achievable by unclamping thededicated access branch which can then be closed off (sutured, fusedetc.) or optionally in some cases attached to a natural vessel toprovide an alternative blood flow path.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details of the disclosed endoprosthetic devices and methods ofuse thereof are disclosed in the following description referring to theaccompanying illustrative drawings in which:

FIG. 1 is schematic side view of a defective (aneurysmic) aorta part ofthe vasculature and showing the minimally invasive entry point forendovascular intervention as a puncture below the diaphragm;

FIG. 2 is a schematic side view of an endoprosthetic device comprisingan upper stented tubular part and a lower branched tubular body;

FIG. 3 is a schematic frontal view of a purse-string suture around anopen end of a vessel forming part of the vasculature requiring anintervention;

FIG. 4 is a schematic side view of an open ended and clamped branch ofthe branched tubular body attached to a side of the patient iliac sothat the attached branch is in flow communication therewith;

FIG. 5 is a schematic side view of the insertion of the compact sheathedstented tubular part through the purse-string suture into a vesselforming part of the vasculature requiring an intervention;

FIG. 6A is a schematic illustration (external demonstration only awayfrom a surgical site) of an initial step in manipulation of a deliverysystem bearing the endoprosthetic device for retraction of a sheath forthe deployment of the stented tubular part when inserted into a vesselforming part of the vasculature as illustrated in FIG. 5;

FIG. 6B is a schematic illustration of a step for removing a sheathsplitter mechanism from around the branched tubular body of theendoprosthetic device, and showing a deployed (expanded) stented tubularpart to the right of the sheath splitter mechanism;

FIG. 6C is a schematic illustration of a step for pulling out andremoving a release clip and wire;

FIG. 6D is a schematic illustration of a step for pulling out andremoving a handle and remainder of delivery system;

FIG. 6E is a schematic illustration of a step for using the accessbranch and a clamp to allow retrograde perfusion to displace aircontrollably from the endoprosthetic device.

FIG. 6F is a schematic illustration of the final step of unclamping theclamped branch of the branched tubular body attached to a side of thepatient iliac which is done at the same time as closing the accessbranch.

FIG. 7A is a perspective view from above and behind from the proximalend of a delivery shaft passing through a portion of the access branchof the endoprosthetic device (the remainder of which is not shown forthe purposes of illustration) upon which a sheath splitter mechanism islocated;

FIG. 7B is a perspective view from above and behind from the proximalend of a delivery shaft bearing a slidable stopper member that islocatable within the access branch of the endoprosthetic device and thesheath splitter mechanism shown inFIG. 7A; and

FIG. 7C is an end elevation of a sheath splitter mechanism, illustratinga splitter chamber within which internal side wall surfaces offercontact surfaces for engaging with the slidable stopper member showninFIG. 7A;

FIG. 8A is a schematic sectional view of a haemostatic seal “valve”mechanism illustrating the relative positioning of the elongate deliveryshaft, stopper member and branch lumen whereby a haemostatic seal isachievable, as viewed in the longitudinal axial direction along theelongate delivery shaft; and

FIG. 8B is a schematic sectional view of a haemostatic seal “valvemechanism illustrating the relative positioning of the elongate deliveryshaft, stopper member and branch lumen whereby a haemostatic seal isachievable, as viewed from one side of hub mounted upon the elongatedelivery shaft.

DETAILED DESCRIPTION OF THE INVENTION

Description of various embodiments follows with the understanding thatthese are for illustrative and non-limiting disclosure purposes.

In the present disclosure, if the term “proximal” is used in relation topart of a delivery system it means the part nearest to a user of thedelivery system.

The term “distal” if used herein in relation to part of a deliverysystem means that part farthermost from a user of the delivery system.

The term “proximal” if used herein in relation to part of an implantedendoprosthetic device means the part nearest to the heart of a patienttreated with the implanted endoprosthetic device.

The term “distal” if used herein in relation to part of an implantedendoprosthetic device means the part remote from the heart of a patienttreated with the implanted endoprosthetic device.

An embodiment similar to the endo prosthetic device disclosed herein maybe used in a procedure to replace the aortic arch and to repair aneurysmand/or dissection of the descending aorta in a single surgicalprocedure.

An embodiment of the endoprosthetic device may comprise a stentedtubular part having a main lumen of a length L_(t), and a branchedtubular body, which has multiple lumens and in a preferred embodiment isbifurcated, the branched tubular body having a length L_(b) connected tothe stented tubular part such that the overall length of theendoprosthetic device comprises length L_(t) plus length L_(b). Thebifurcated branched tubular body may comprise substantially paralleltubular limbs extending from the stented tubular part axially withrespect to a longitudinal axis through the main lumen of the stentedtubular part. These substantially parallel tubular limbs are configuredto be attachable to the iliac arteries of a patient.

The bifurcated branched tubular body may comprise limbs respectively ofa length Lb₁ and Lb₂, where Lb₁ and Lb₂ may be the same length or ofdiffering lengths.

The size of endoprosthetic device may be such that L_(t) may be in therange of from 20 mm to 300 mm; and L_(b), or Lb₁ and Lb₂ may be up to400 mm.

Typically the branch lumens may have a length L_(bv) of up to 300 mm.

The branch lumens would be designed to match patient natural vesselsizes, and may range from 4 to 20 mm in diameter. A branch lumenintended as being suitable for use as an access branch may also be from4 to 20 mm in diameter.

In an embodiment, the deployed (in the fully opened configuration)stented tubular part may have a diameter of 12 to 50 mm. The branchedtubular body may also have a diameter of 12 to 50 mm. In embodiments thebranched tubular body may be of smaller diameter than the stentedtubular part.

In some embodiments, the branched tubular body is tapered. For example,a taper from the stented tubular part down to the bifurcated branchedtubular body of 2 to 14 mm may be required to account for geometryvariation and stent oversizing etc.

The bifurcated branched tubular body may comprise tubular limbs havinglumens of lesser cross-sectional dimensions than the main lumen of thestented tubular part, and the tubular limbs may have equivalent ordiffering cross-section dimensions in comparison of one tubular limb tothe other tubular limb.

If necessary to match natural vessels in a patient, a reduction incross-section dimensions can be achieved in the bifurcated branchedtubular body by providing a tapered tubular part.

Typically the natural vessels of the vasculature may differ from patientto patient in terms of size, configuration and location. Therefore theendoprosthetic device may have to be “customised” for example cut tosize during the procedure or potentially the intended allocation ofbranches of the branched tubular body may need to be changed tocompensate for unforeseen peculiarities of the unique vasculature of thepatient. The endoprosthetic device may be manufactured with distalclosed end or blind branches so that a choice can be made by the user ofthe device (surgeon, or surgical assistant) can selectively open abranch. In embodiments the distal closed end or blind branches can becreated by provision of removable sutures, or by incorporating aremovable valve at the open end of respective branches of the branchedtubular body.

The branched tubular body may have multiple tubular branches extendingoutwardly from the endoprosthetic device in a number sufficient to beattachable respectively to visceral vessels and also have at least oneaccess branch for a minimal access surgical step, for example forinsertion of an instrument or a delivery system tool and optionally forde-airing of the device during a surgical procedure. The at least oneaccess branch may have greater lumen dimensions (length and orcross-sectional area) than any of the multiple tubular branches thatwould be extending laterally and attachable to visceral vessels.

More than one access branch may be provided at respectively alternativeaccess positions on the branched tubular body.

One or more of the multiple tubular branches may be configured to extendlaterally from the branched tubular body with respect to a longitudinalaxis through the main lumen of the branched tubular body. This allowsfor lateral branch flow of blood from the main lumen of the branchedtubular body to major vessels to restore vascular functionality as viaany of the natural visceral vascular branches of the abdominal aorta.

The at least one access branch in any embodiment may be used forde-airing the endoprosthetic device used in a hybrid procedure during orafter removal of instruments or delivery system parts and tools.

During a hybrid procedure using the endoprosthetic device disclosedherein, when the endoprosthetic device is connected to a natural vessel,particularly one of the iliac arteries, air can be vented (naturalescape by displacement) through an unconnected (open) branch andperfusion is simultaneously achievable by retrograde blood flow.

In an embodiment the stented tubular part is a stent graft. The stentgraft may comprise a conduit formed from a flexible sleeve attached to arigid support or stent. The sleeve will typically be made of a fabric(usually a knitted or woven fabric) of ePTFE, PTFE or polyester,polyethylene or polypropylene and may optionally be coated to reducefriction; discourage clotting or to deliver a pharmaceutical agent. Thefabric will generally be porous on at least one surface to enable cellingrowth. The stent may be balloon-expandable (eg. a PALMAZ stent madeof rigid stainless steel wire), but could also be self-expandable andformed of a shape memory material, such as nitinol (a nickel-titaniumalloy). Numerous different stent designs are known in the art, forexample braided stents as described in EP 0 880 979 or wire zig-zagstents as described in U.S. Pat. No. 4,580,568.

Stent grafts are commonly formed with a plurality of stents spaced alongthe graft. Even spacing of the stents ensures that the crush strength ofthe graft does not vary along its length. However, whilst the spacingbetween the stents allows the graft to be curved when inserted in a bodyvessel, the degree of curvature is limited by the stent spacing. WO2010/053563 describes a stent graft designed for deployment in a curvedvessel. Identical stents are spaced further apart from each other in theregion of the stent graft which undergoes the greatest curvature. Thus,the inter-stent spacing varies along at least part of length of thegraft. However, for treatment of aneurysm, it is desirable that thestent graft exhibits a degree of stiffness across the diseased(aneurismitic) portion of the blood vessel under repair.

A suitable stent graft for an embodiment of the present hybridendoprosthetic device may comprise a plurality of separate, unconnectedring stents, selectable from ring stent types comprising a planarcircular ring, and sinusoidal- or “saddle”-shape ring stents. A saddleshape ring stent is one that when first formed is an individual circularring stent that is normally planar, but formed of a material which issufficiently resilient to be distorted so that a first pair ofdiametrically opposed points on the circumference of the ring stent aredisplaced in one axial direction whilst a second pair of diametricallyopposed points, centrally located on the circumference between the firstpair, are displaced in the opposing axial direction to form asymmetrical “saddle” shape. For convenience, the first pair of pointscan be described as “peaks”, with the second pair of points beingdescribed as “valleys”. The degree of axial displacement between thefirst pair of points and the second pair of points (which axialdisplacement is also termed the “saddle height”), is a function of theoriginal circumference of the ring stent prior to its distortion,relative to the final circumference of a circle within which thedistorted (saddle shaped) configuration can be located. Thus, the ratioof final circumference:original circumference provides a simplisticnotation of the axial displacement. Generally the final circumferencewill be the outer circumference of the graft sleeve to which the stentis to be attached. The percentage oversize of the undistorted innercircumference of the circular stent relative to the outer circumferenceof the graft sleeve also gives a convenient measure of the saddle shapeadopted, and can be calculated as:

${{Oversize}\mspace{14mu} \%} = {\frac{\left\lbrack {{{Stent}\mspace{14mu} {inner}\mspace{14mu} {diameter}} - {{Graft}\mspace{14mu} {sleeve}\mspace{14mu} {outer}\mspace{14mu} {diameter}}} \right\rbrack}{{Graft}\mspace{14mu} {sleeve}\mspace{14mu} {outer}\mspace{14mu} {diameter}} \times 100\%}$

Other forms of stent can be used instead of the aforesaid ring stents.Spiral, Z- or zig-zag, and tubular mesh types and combinations of any ofthese types with or without ring stents may also be suitable.

According to another aspect, in an embodiment of the endoprostheticdevice described above, each one of the multiple branches, or a selectednumber of the multiple branches of the branched tubular bodyrespectively may have a lumen that is initially closed to passage offluid. This is achievable by forming the branch or respective branchesextending from the tubular body with a distal closed or blind end. Inembodiments the distal closed end or blind branches can be created byprovision of removable sutures, or by incorporating a removable valve atthe open end of respective branches of the branched tubular body.

Providing distal closed end branches permits improved control ofperfusion through the endoprosthetic device via the connected mainlumens respectively of the branched tubular part and the stented part ofthe endoprosthetic device. In such embodiments perfusion into thestented part of the endoprosthetic device and out one of the limbs ofthe bifurcated branched tubular body allows the endoprosthetic device toserve as a temporary bypass during a surgical procedure, for example toocclude an aneurysm. A selected one of the multiple branches of thebranched tubular body which may have a lumen that is initially closedcan be opened to serve as an access branch for a minimal access surgicalor procedural step.

An advantage of use of the endoprosthetic device with initially closedend branches is that there is reduced need for extra-corporeal bypassand lessened requirement for initiating cardiac arrest because perfusionthrough the hybrid endoprosthetic device permits substantiallycontinuous perfusion of the patient during the reattachment of thevisceral vascular vessels to the selectively opened branches on thebranched tubular body of the endoprosthetic device.

This feature of the endoprosthetic device allows for substantiallynormal blood pressure to be sustainable for extended periods byperfusion during the procedure.

In embodiments where multiple branches of the branched tubular bodyrespectively have a lumen that is initially closed to passage of fluidby means of a distal closed or blind end, the said multiple branches canbe selectively and sequentially opened for connection with a naturalvessel, without detrimentally interrupting perfusion through theendoprosthetic device, by opening the selected distal closed or blindend, for example by removal of sutures or using a valve dedicated to thebranch to be opened.

The branched tubular body may be made from a woven fabric.

An embodiment of the endoprosthetic device is configured for delivery atleast in part in a compact form within a delivery system upon anelongate shaft, guide wire or catheter. An optional stopper member maybe moveably mounted upon the elongate shaft, guide wire or catheter tocooperate with a clamping device which may be part of the deliverysystem and provide a haemostatic seal against the wall of a branch ofthe branched tubular body used as the access branch for the deliverysystem.

In an embodiment, a clamping device may be positioned over the accessbranch at a location where the stopper member is positioned and theclamping device is then clamped around the access branch to compress thewall of the access branch against the stopper member. This combinationof cooperating parts provides a “valve mechanism” offering a haemostaticseal during a surgical procedure. Whilst the clamping device, wall ofthe access branch and stopper member are cooperating as a “valvemechanism”, the elongate shaft, guide wire or catheter can be movedrelative to the “valve mechanism” without significant loss of bloodbecause the stopper member is moveably mounted on the elongate shaft,guide wire or catheter but restrained by the clamping device acting onthe access branch to stop the stopper member from moving whilst theelongate shaft is moved.

The clamping device may comprise a hub having an axial throughboreproviding a lumen admitting an elongate shaft and capable of receiving apart length of the wall of an access branch of an endoprosthetic device.The hub may comprise a rotatable collar mounted upon a threaded part ofthe hub and cooperating with a corresponding compressible internal partof the hub so that when the rotatable collar is turned along thethreaded part, the collar and the compressible part come into contactand the compressible part reduces the dimensions of the lumen of theaxial throughbore. Such reduction in dimensions of the lumen of theaxial throughbore allows for compression of the part length of the wallof an access branch against the stopper member when the stopper memberis appropriately positioned within the hub at the compressible part. Thehub may have an internal chamber around the axial throughbore havingwall parts suitable for providing an abutment with the stopper member sothat it is appropriately positioned within the hub.

The rotatable collar may be rotated manually, and may have a first lobepositioned on a surface thereof to encounter a corresponding second lobeon the hub when the rotatable collar reaches the end of the threadedpart whereby applying slightly increased turning force bumps the firstlobe over the second lobe to inhibit reverse rotation of the rotatablecollar at the end of the threaded part. In this way after the user letsgo of the rotatable collar the compression applied thereby to thecompressible internal part is maintained.

A friction-reducing or slip material such as a physiologically inert orphysiologically benign polymer or polymer blend may be applied as acoating on a surface of the stopper member. This surface would be atleast one surface that in use makes sliding contact with the elongateshaft, guide wire or catheter. A smooth ceramic or glass coating may beused as an alternative to a polymer for slip surfaces in sliding contactwith the elongate shaft, guide wire or catheter.

Useful polymeric coating materials which are flexible includepolymerised hydrofluorocarbons (e.g. PTFE), and silicones.

The stopper member may be encapsulated in such a flexible reduced slipmaterial.

In embodiments, the stopper member may be formed of a compressible butresilient material such as a silicone rubber.

A silicone rubber stopper member with a smooth silicone coating mayprovide a useful practical form for the purpose of forming a haemostaticseal with the access branch side wall when compressed by the clampingdevice.

The stopper member may have a modified surface, as by etching, toimprove functionality.

The stopper member may be shaped to incorporate a groove to facilitatesliding along the elongate shaft.

An advantage of this arrangement of the juxtaposed hub, stopper memberand access branch side wall, which thereby serves as a haemostatic“valve mechanism” is that the elongate shaft, guide wire or catheterused for delivery can be withdrawn until a tip of the elongate shaft,guide wire or catheter is captured within a selected portion of theaccess branch, an additional clamp may be applied just forward of thetip of the elongate shaft, guide wire or catheter to the access branch.This then allows the elongate shaft, guide wire or catheter to be fullywithdrawn together with any delivery system components carried thereonwith minimal blood loss through the access branch. Unless required forany additional procedure or for use in connection to a natural vessel,the access branch can be closed off for example by suturing close to thebranched tubular body and the additional clamp removed.

A delivery system to be used for delivery of the endoprosthetic devicesubject of the present disclosure, comprises a malleable shaft adaptedto be formed manually by a user if required to a preferred curvaturewhereby the malleable shaft may conform better to a patient's anatomy.The shaft may have a smooth atraumatic distal tip and a plurality ofaccess ports located at the distal tip for receiving a guide wire tofacilitate delivery of the endoprosthetic device through a naturallumen. The distal tip may have a tapered or pointed shape.

The endoprosthetic device subject of the present disclosure can becompactly packaged for delivery upon the malleable shaft of the deliverysystem in a manner generally known in the field by use of a removablesheath over the stented tubular part. A combination of releasable clips,fasteners and sutures can be used to hold the endoprosthetic device in acompact packaged configuration in the delivery system.

A thin sheath for constraining the stented tubular part of theendoprosthetic device upon the malleable shaft for delivery may comprisea smooth polymeric material. A polymerised hydrofluorocarbon such asPTFE is suitable.

The retractable sheath may alternatively be formed frompolyethyleneterephthalate (PET). The selected material should be onewhich is biocompatible and may be readily passed through natural vesselsor artificial lumens without sticking. The retractable sheath may besurface treated, for example to impart or enhance hydrophilic propertiesby applying a hydrophilic coating.

Suitable polymeric flexible materials for the retractable sheath may beselected from thermoplastic polymers, elastomers, and copolymers such asnylon, polyurethane, polyethylene (PE), polytetrafluoroethylene (PTFE),expanded polytetrafluoroethylene (ePTFE), fluorinated ethylenepropylene, polyether block amides (PEBA), polyimide, polyether etherketone, and polybutylene terephthalate.

The retractable sheath may be of a multi-layered construction offlexible, polymeric materials, such as multi-layered extrusions,optionally reinforced as by use of braided layered assemblies or laminarstructures incorporating bonding layers and reinforcements, orintermittent extruded composite extrusions and assemblies of variabledurometer characteristics.

An embodiment of a delivery system may further comprise a sheath removalmechanism which includes at least one slitter element for parting thesheath longitudinally to allow the constrained stented tubular part ofthe endoprosthetic device to expand into its deployed configuration, anda sheath removal element, such as a pull strap, cord, tape, wire or thelike, connected to the sheath to allow removal of the sheath.

The slitter element may be fixed to or located within a hub that isremovably mounted upon an elongate malleable delivery shaft.

The hub may comprise two part-cylindrical parts adapted to fit aroundthe elongate delivery shaft (and guide wire when used) and be clipped orremovably fastened together. Suitably the hub part-cylindrical parts canhave internal surfaces configured to clamp down upon a part length ofthe wall of a branch of the branched tubular body used as the accessbranch when that part length is positioned within the hub.

In embodiments the hub may have protruding parts formed to have aslitting edge to provide a slitter element for splitting the sheathduring retraction of the sheath to allow deployment of the stentedtubular part of the endoprosthetic device.

The delivery system may further comprise a user manoeuvring controlhandle attached to one end of the elongate malleable delivery shaftremote from the distal tip to allow a user to move, manipulate andcontrol the positioning of the delivery system, and the deployment ofthe endoprosthetic device to be deployed therefrom.

A unique aspect of delivery of the endoprosthetic device disclosedherein is that it is delivered in the opposite direction (retrogradeinsertion) from that observed in the field in the conventional so-called“elephant trunk” technique which can be used in a staged thoracic aorticsurgery (Borst H G, Walterbusch G, Schaps D. Extensive aorticreplacement using “elephant trunk” prosthesis. Thorac Cardiovasc Surg1983; 31:37-40).

In an embodiment of a method involving use of the endoprosthetic devicesubject of the present disclosure the patient is prepared for surgery inaccordance with leading standards of surgical practice and in line withgood medical practice guidelines.

Following preparation of the patient and establishment of the sterilesurgical field, the endoprosthetic device is presented to the surgicalsite using a delivery system including a hub provided with slitterelements, and at least the following steps are taken.

-   -   1. Prepare purse-string suture.    -   2. The iliac may be partially clamped, and an incision made. One        of the limbs of the bifurcated branched tubular body serving as        an iliac branch may be anastomosed to patient iliac in an        end-to-side configuration. The clamp may then be released to        admit blood flow into the device whereupon air in the device may        be displaced from the device iliac branch and clamping is        applied to the branch.    -   3. Insert endo stented tubular part into purse string incision        below patient's diaphragm and maneouver to position the stented        tubular part within the target defective natural vessel lumen,        typically seeking to engage with an unaffected part of the        thoracic aorta (notably this would be a retrograde/reversed        insertion as compared with usual “Elephant trunk” procedure for        thoracic aortic interventions).    -   4. Deploy endo stented tubular part of the endoprosthetic device        by maneouvring the delivery system and remove the delivery        system parts by taking steps including        -   i. Retract the sheath over the stented tubular part, using a            pull strap to bring the sheath against the hub equipped with            slitter elements in the delivery system thus splitting the            sheath and allowing the stented tubular part to expand to            open the main lumen thereof thereby immediately admitting            blood flow for perfusion through aorta.        -   ii. Release each fastener, wire or any suture holding the            hub and slitter elements into assembly with the            endoprosthetic device and separate these parts of the            delivery system.        -   iii. Remove remaining delivery system locking or retention            parts such as a release clip and withdraw guide wire.        -   iv. Remove delivery system handle and all remaining parts of            delivery system from patient.        -   v. De-air implanted endoprosthetic device using access            branch.        -   vi. Clamp access branch and simultaneously open clamped            iliac branch of bifurcated branched tubular body.    -   5. Attach auxiliary vessels one at a time to respectively each        one of the multiple branches of the branched tubular body to        perfuse visceral arteries.    -   6. Attach second endoprosthetic device iliac branch (second one        of limbs of bifurcated branched tubular body to patient    -   7. Reattach 1^(st) iliac end-to-end    -   8. Open aneurysm sac and finish operation

In another embodiment of a surgical procedure using the presentlydisclosed endoprosthetic device and a delivery system including a sheathsplitter comprising a hub equipped with slitter elements aligned axiallywith respect to a delivery shaft of the delivery system, at least thefollowing steps are taken.

-   -   1. Prepare purse-string suture.    -   2. The iliac may be partially clamped, and an incision made. One        of the limbs of the bifurcated branched tubular body serving as        an iliac branch may be anastomosed to patient iliac in an        end-to-side configuration to allow a lumen of the endoprosthetic        device iliac branch to fluidly communicate with the lumen of the        patient iliac for subsequent perfusion.    -   3. Insert endo stented tubular part into purse string incision        below patient's diaphragm and maneouver to position the stented        tubular part within the target defective natural vessel lumen,        typically seeking to engage with an unaffected part of the        thoracic aorta (notably this would be a retrograde/reversed        insertion as compared with usual “Elephant trunk” procedure).    -   4. Deploy endo stented tubular part of the endoprosthetic device        by maneouvring the delivery system and remove the delivery        system parts by taking steps including        -   i. Retract the sheath over the stented tubular part, using a            pull strap to bring the sheath against the hub equipped with            slitter elements in the delivery system thus splitting the            sheath and allowing the stented tubular part to expand to            open the main lumen thereof thereby immediately admitting            blood flow for perfusion through the aorta.        -   ii. Remove delivery system locking or retention parts such            as a release clip and withdraw guide wire.        -   iii. Hold hub equipped with slitter elements and retract            delivery system through hub equipped with slitter elements            until the delivery shaft tip is fully enclosed in the access            branch        -   iv. Clamp the access branch proximal to the tip        -   v. Either cut access branch to remove the branch and            delivery system from the device or cut the splitter suture            and remove the splitter and delivery system while retaining            the length of the access branch        -   vi. De-air device using access branch (by removing/replacing            clamp)        -   vii. Once de-aired, unclamp the device iliac    -   5. Attach auxiliary vessels one at a time    -   6. Attach 2^(nd) iliac    -   7. Reattach 1^(st) iliac end-to-end    -   8. Open aneurysm sac and finish operation

Referring to FIG. 1, a distended aorta 11 connected with the commoniliac part of the vasculature is illustrated. The bifurcation of thecommon iliac into first and second iliac arteries 12, 13 respectively isalso illustrated. In this illustration the aorta is aneurysmic. In othercircumstances the common iliac may be aneurysmic. The disclosed deviceis designed to treat a range of aortic and iliac aneurysm states. Aminimally invasive access to the aorta is provided to the intendedsurgical site by way of the small incision 15 around which a pursestring suture as illustrated in FIG. 3 is formed. A side entry incision14 in an iliac artery is also made for purposes to be discussed below.

Referring to FIG. 2, a hybrid endoprosthetic device 20 comprises astented tubular part 21 including a sleeve 22 defining a lumen 23 and abranched tubular body 25 connected such that the lumen 23 of the stentedtubular part 21 communicates with a main lumen 24 of the branchedtubular body 25. The branched tubular body 25 includes a first tubularbody portion 26 having a length L_(t), and a bifurcated branched tubularbody 36, having a length L_(b) extending from the first tubular bodyportion 26 such that the length of the branched tubular body 25comprises length L_(t) plus length L_(b). The bifurcated branchedtubular body 36 may comprise a pair of tubular limbs 37, 39 extending ina divergent configuration from the first tubular body portion 26 withrespect to a longitudinal axis through the main lumen 24 of the firsttubular body portion 26.

The bifurcated branched tubular body 36 may have limbs respectively of alength Lb₁ and Lb₂, where Lb₁ and Lb₂ may be the same length or ofdiffering lengths.

The bifurcated branched tubular body 36 may comprise tubular limbs 37,39 having lumens of lesser cross-section dimensions than the main lumen24 which extends into the first tubular body portion 26, and in thisembodiment the tubular limbs have equivalent cross-section dimensions incomparison of one tubular limb to the other tubular limb.

In some embodiments, a taper from the stented tubular part down to thebifurcated branched tubular body of 2-14 mm may be required to accountfor geometry variation and stent oversizing etc.

The illustrated branched tubular body 25 has multiple tubular branches27, 28, 29, extending outwardly from the first tubular body portion 26and an access branch 38 for a minimal access surgical step forintroducing the stented tubular part 21 into the aorta (as illustratedin FIG. 5) which access branch may have greater lumen dimensions (lengthand or cross-sectional area) than any of the multiple tubular branches27, 28, 29.

One or more of the multiple tubular branches 27, 28, 29 may beconfigured to extend laterally from the first tubular body portion 26with respect to a longitudinal axis through the first tubular bodyportion 26. This allows for lateral branch flow of blood from the mainlumen of the branched tubular body to major vessels to restore vascularfunctionality as via any of the natural visceral vascular branches ofthe abdominal aorta.

The at least one access branch 38 may be used for manipulating thedelivery system, de-airing the hybrid endoprosthetic device and removingthe delivery system from the hybrid endoprosthetic device.

FIGS. 6A to 6E illustrate (for demonstration purposes remote from asurgical site), the steps required for retracting a sheath used todeliver the stented tubular part 21 into the aorta in a compact form,the said retraction permitting deployment of the stented tubular part 21into the aorta, and subsequent steps for removing the delivery systemand venting air from the endoprosthetic device, and use of clamps toclose off the access branch 38, and allow blood flow by unclamping theiliac branch 39.

Referring now to FIGS. 7A to 7C, an elongate malleable delivery shaft 71is illustrated within a hub 72 including a splitter mechanism 73, thehub 72 being located around the access branch 38 shown in FIG. 7A, and astopper member 74 is slidably mounted upon the elongate malleabledelivery shaft 71 as shown in FIG. 7B without the hub 72 forillustration purposes. FIG. 7C shows an end view looking along the axiallength of the elongate malleable delivery shaft 71.

Referring now to FIGS. 8A, and 8B, FIG. 8A schematically illustrates anelongate malleable delivery shaft 81 within a portion of an accessbranch 88, which in turn is positioned within a hub 82, and a stoppermember 84 is slidably mounted upon the elongate malleable delivery shaft81. FIG. 8B shows an end view looking along the axial length of theelongate malleable delivery shaft 81.

In another embodiment of similar purpose to that illustrated in FIGS. 8Aand 8B the endoprosthetic device is configured for delivery at least inpart in a compact form within a delivery system upon an elongate shaft,guide wire or catheter. The delivery system includes a stopper member orsealing element which may be moveably mounted upon the elongate shaft,guide wire or catheter to cooperate with a clamping device which may bepart of the delivery system. The stopper member performs a function ofpromoting a haemostatic seal by pressing against part of the wall of abranch of the branched tubular body used as the access branch for thedelivery system, and that pressed part of the wall in turn is contactedby the clamping device.

In an embodiment, a clamping device may be positioned over the accessbranch at a location where the stopper member is positioned and theclamping device is then clamped around the access branch to compress thewall of the access branch against the stopper member. This combinationof cooperating parts provides a “valve mechanism” offering a haemostaticseal during a surgical procedure. Whilst the clamping device, wall ofthe access branch and stopper member are cooperating as a “valvemechanism”, the elongate shaft, guide wire or catheter can be movedrelative to the “valve mechanism” without loss of blood because thestopper member is moveably mounted on the elongate shaft, guide wire orcatheter but restrained by the clamping device acting on the accessbranch to stop the stopper member.

A friction-reducing or slip material such as a physiologically inert orbenign polymer or polymer blend may be applied as a coating on a surfaceof the stopper member. This surface would be at least one that in usemakes sliding contact with the elongate shaft, guide wire or catheter. Asmooth ceramic or glass coating may be used as an alternative to apolymer for slip surfaces in sliding contact with the elongate shaft,guide wire or catheter.

Useful polymeric coating materials include polymerisedhydrofluorocarbons (e.g. PTFE), and silicones.

The stopper member may be encapsulated in such a reduced slip material.

In embodiments, the stopper member may be formed of a compressible butresilient material such as a silicone rubber.

A silicone rubber stopper member with a smooth silicone coating mayprovide a useful practical form for the purpose of forming a haemostaticseal with the access branch side wall when compressed by the clampingdevice.

An advantage of this “valve mechanism” is that the elongate shaft, guidewire or catheter used for delivery can be withdrawn until a tip of theelongate shaft, guide wire or catheter is captured within a selectedportion of the access branch, an additional clamp may be applied justforward of the tip of the elongate shaft, guide wire or catheter to theaccess branch. This then allows the elongate shaft, guide wire orcatheter to be fully withdrawn together with any delivery systemcomponents carried thereon with minimal blood loss through the accessbranch. Unless required for any additional procedure or for use inconnection to a natural vessel, the access branch can be closed off forexample by suturing close to the branched tubular body and theadditional clamp removed.

The hub may comprise two part-cylindrical parts adapted to fit around adelivery shaft (and guide wire when used) and be clipped or removablyfastened together. Suitably the hub part-cylindrical parts can haveinternal surfaces configured to clamp down upon the access branch whenpositioned therein.

The hub may form part of a delivery system as described for embodimentshereinbefore to be used for delivery of the endoprosthetic devicesubject of the present disclosure.

Referring now to FIG. 9, an embodiment of the hybrid endoprostheticdevice 90 comprises a stented tubular part 91 including a sleeve 92defining a lumen 93 and a branched tubular body 95 connected such thatthe lumen 93 of the stented tubular part 91 communicates with a mainlumen of the branched tubular body 95. The stented tubular part 91comprises a series of ring stents 94 having a “saddle” shape. Thebranched tubular body 95 includes a first tubular body portion 96 havinga length L_(t), and a bifurcated branched tubular body 66, having alength L_(b) extending from the first tubular body portion 96 such thatthe length of the branched tubular body 95 comprises length L_(t) pluslength L_(b). The bifurcated branched tubular body 66 may comprise apair of tubular limbs 67, 69 extending axially from the first tubularbody portion 96 with respect to a longitudinal axis through the mainlumen of the first tubular body portion 96.

The bifurcated branched tubular body 66 may have limbs respectively of alength Lb₁ and Lb₂, where Lb₁ and Lb₂ may be the same length or ofdiffering lengths.

The bifurcated branched tubular body 66 may comprise tubular limbs 67,69 having lumens of lesser cross-section dimensions than the main lumenwhich extends into the first tubular body portion 96, and in thisembodiment the tubular limbs have equivalent cross-section dimensions incomparison of one tubular limb to the other tubular limb.

In some embodiments, a taper from the stented tubular part down to thebifurcated branched tubular body of 2-14 mm may be required to accountfor geometry variation and stent oversizing etc.

The illustrated branched tubular body 95 has multiple tubular branches79, 97, 98, 99, extending outwardly from the first tubular body portion96 and an access branch 68 for a minimal access surgical step forintroducing the stented tubular part 91 into the aorta (as illustratedin FIG. 5) which access branch may have greater lumen dimensions (lengthand or cross-sectional area) than any of the multiple tubular branches79, 97, 98, 99.

One or more of the multiple tubular branches 79, 97, 98, 99 may beconfigured to extend laterally from the first tubular body portion 96with respect to a longitudinal axis through the first tubular bodyportion 96. This allows for lateral branch flow of blood from the mainlumen of the branched tubular body to major vessels to restore vascularfunctionality as via any of the natural visceral vascular branches ofthe abdominal aorta

The at least one access branch 68 may be used for manipulating thedelivery system, de-airing the hybrid endoprosthetic device and removingthe delivery system from the hybrid endoprosthetic device.

A collar 61 to aid anastomosis to a natural vessel is fixed around theendoprosthetic device at a portion thereof where the stented tubularpart and branched tubular body are connected.

The stented tubular part is provided with hooks 64 for retention of thestented tubular part in a selected position when deployed in a lumen ofa natural vessel.

The stented tubular part is provided with a radiopaque marker 65 toimprove in vivo visualisation and to facilitate precise positioning ofthat part of the device.

All documents referred to in this specification are herein incorporatedby reference. Various modifications and variations to the describedembodiments of the inventions will be apparent to those skilled in theart without departing from the scope of the invention as defined in theclaims. Although the invention has been described in connection withspecific preferred embodiments, it should be understood that theinvention as claimed should not be unduly limited to such specificembodiments. Indeed, various modifications of the described modes ofcarrying out the invention which are obvious to those skilled in the artare intended to be covered by the present invention.

Reference Numerals used in the Drawings

-   11 aorta-   12 first iliac artery-   13 second iliac artery-   14 side entry incision in an iliac artery-   15 small incision with a purse string suture-   20 a hybrid endoprosthetic device-   21 endo stented tubular part-   22 sleeve for endo stented tubular part-   23 lumen within endo stented tubular part-   24 main lumen of the branched tubular body-   25 branched tubular body-   26 first tubular body portion of branched tubular body-   27 tubular branch of branched tubular body-   28 tubular branch of branched tubular body-   29 tubular branch of branched tubular body-   36 bifurcated branched tubular body portion of branched tubular body    (FIG. 2)-   37 tubular limb of bifurcated branched tubular body portion (iliac)-   38 access branch of branched tubular body (FIG. 2)-   39 tubular limb of bifurcated branched tubular body portion (iliac)-   61 collar to aid anastomosis-   64 hooks for locating endo stented tubular part in natural lumen-   65 radiopaque marker-   66 bifurcated branched tubular body (FIG. 9)-   67 tubular limb of bifurcated branched tubular body portion (FIG. 9)-   68 access branch of branched tubular body (FIG. 9)-   69 tubular limb of bifurcated branched tubular body portion (FIG. 9)-   71 elongate malleable delivery shaft-   72 hub including a splitter mechanism-   73 splitter mechanism-   74 stopper member-   79 tubular branch of branched tubular body (FIG. 9)-   81 elongate malleable delivery shaft (FIGS. 8A &8B)-   82 hub without splitter mechanism-   84 stopper member (FIGS. 8A & 8B)-   88 access branch (FIGS. 8A & 8B)-   90 hybrid endoprosthetic device (FIG. 9)-   91 endo stented tubular part (FIG. 9)-   92 sleeve for endo stented tubular part (FIG. 9)-   93 lumen within sleeve for endo stented tubular 95 part-   95 branched tubular body (FIG. 9)-   96 first tubular body portion (FIG. 9)-   97 tubular branch of branched tubular body (FIG. 9)-   98 tubular branch of branched tubular body (FIG. 9)-   99 tubular branch of branched tubular body (FIG. 9)

1. A hybrid endoprosthetic device comprising a stented tubular part anda branched tubular body connected such that a main lumen of the stentedtubular part communicates with a main lumen of the branched tubularbody, wherein the branched tubular body has multiple branch lumens forconnection with natural vessels of the vasculature, and includes atleast one branch lumen for access to facilitate delivery andimplantation of the hybrid endoprosthetic device by an endovascular stepin a hybrid surgical procedure, and the hybrid endoprosthetic device isconfigured to replace a part of the aorta and common iliac artery. 2.The hybrid endoprosthetic device claimed in claim 1, wherein themultiple branch lumens of the branched tubular body comprise multipletubular branches extending laterally from the branched tubular body withrespect to a longitudinal axis through the main lumen of the branchedtubular body.
 3. The hybrid endoprosthetic device claimed in claim 1,wherein the branched tubular body comprises a bifurcated part.
 4. Thehybrid endoprosthetic device claimed in claim 3, wherein the bifurcatedpart comprises substantially parallel tubular limbs extending from thestented tubular part axially with respect to a longitudinal axis throughthe main lumen of the stented tubular part.
 5. The hybrid endoprostheticdevice claimed in claim 1, wherein the branched tubular body is tapered.6. The hybrid endoprosthetic device claimed in claim 1, wherein a collaris provided around the hybrid endoprosthetic device at a portion thereofwhere the stented tubular part and branched tubular body are connected,and the collar provides a flanged portion suitable for anastomosis to anatural vessel of the vasculature.
 7. The hybrid endoprosthetic deviceclaimed in claim 1, wherein the at least one branch lumen for access hasgreater lumen dimensions than the multiple branch lumens.
 8. The hybridendoprosthetic device claimed in claim 1, wherein the multiple branchlumens are formed in multiple branches respectively having a distalclosed end.
 9. The hybrid endoprosthetic device claimed in claim 8,wherein the distal closed end is closed by removable sutures.
 10. Thehybrid endoprosthetic device claimed in claim 8, wherein the distalclosed end is closed by removable valves.
 11. A delivery system for usewith the hybrid endoprosthetic device as claimed in claim 1, comprisingan elongate delivery shaft and a handle for manoeuvring control of theelongate delivery shaft, a hub having a throughbore admitting theelongate delivery shaft and capable of receiving a part length of thewall of a branch of the branched tubular body, a stopper member that isslidable axially along the length of the elongate delivery shaft andconfigured to fit into the hub, and sized to form a close fit within thebranch of the branched tubular body such that the stopper membercompresses the part length of the wall of the branch of the branchedtubular body within the hub to form a seal around the elongate deliveryshaft.
 12. The delivery system claimed in claim 11, wherein the hubcomprises a sheath removal mechanism for removing a sheath from thestented tubular part of the hybrid endoprosthetic device, the sheathremoval mechanism comprising at least one slitter element for partingthe sheath longitudinally.
 13. The delivery system claimed in claim 11,comprising a sheath removal element.
 14. A delivery system claimed inclaim 11, wherein the hub comprises two part-cylindrical parts fittedaround the elongate delivery shaft and removably fastened together. 15.A delivery system claimed in claim 14, wherein the hub part-cylindricalparts have internal surfaces configured to clamp down upon a part lengthof the wall of the branch of the branched tubular body.
 16. The hybridendoprosthetic device claimed in claim 1, wherein the multiple branchlumens of the branched tubular body comprise multiple tubular branchesextending laterally from the branched tubular body with respect to alongitudinal axis through the main lumen of the branched tubular body,wherein the branched tubular body comprises a bifurcated part.
 17. Thehybrid endoprosthetic device claimed in claim 16, wherein the bifurcatedpart comprises substantially parallel tubular limbs extending from thestented tubular part axially with respect to a longitudinal axis throughthe main lumen of the stented tubular part.
 18. The hybridendoprosthetic device claimed in claim 2 wherein the multiple branchlumens are formed in multiple branches respectively having distal closedends.
 19. A method of using a hybrid endoprosthetic device, comprising:obtaining a hybrid endoprosthetic device, wherein the device comprises:a stented tubular part having a main lumen and a branched tubular bodyhaving a main lumen, wherein the branched tubular body has multiplebranch lumens for connection with natural vessels of the vasculature ofa person, and includes at least one branch lumen, obtaining a deliverysystem having a hub with a plurality of slitter elements: preparing apurse-string suture; making an incision in the skin and clamping theiliac artery; attaching a limb of the branched tubular body to the iliacartery; releasing the clamp on the iliac and clamping the branch lumen;inserting the stented tubular part into a purse string incision below apatient's diaphragm and positioning the stented tubular part within atarget natural vessel lumen in a retrograde/reversed insertion manner;deploying the stented tubular part of the device via the delivery systemand removing the delivery system from the patient; attaching auxiliaryvessels to the multiple branch lumens of the branched tubular body;attaching a second endoprosthetic device iliac branch to the patient;reattaching the first iliac artery; and closing the incision.